Measurements of Covariance for Cascading Gamma -

An apparatus was developed to measure the covariance and delayed covariance of the counting rates in two gamma ray detectors, where each detector is adjusted to accept one of two cascading gamma rays. The apparatus was used to measure the halflife of the 304 keV level of ('75)As produced in the radioactive decay of ('75)Se. Preliminary measurements of the angular distributions between pairs of gamma rays cascading through the 316 keV level of ('169) Tm, produced in the radioactive decay of ('169)Yb, were also performed.